Leon Sargent writes: >Is it just me or have others noticed that G4 upgrade go as high as 550 MHz >were old world Mac upgrades go as high as 800 and I think there is a dual >version of that as well. > >Is there something that prevents a G3 processor from using the higher >speeds.
AFAIK, the G3 tops out at a multiplier of 10x. Since "PCI upgrades" us a 50 MHz bus, most G3 cards will top out at 500 MHz. On a beige G3, with a 66 MHz bus, the newer G3s with a 10x multiplier would reach 667 MHz, but nobody seems to have designed such an upgrade yet. And it's conceivable that the blue & white G3 could support 1 GHz G3s, were IBM to ship such a CPU. There are new G4 chips that support a 16x multiplier, and I've read comments on 20x as well. Thus a G4 on a 50 MHz bus could reach 800 MHz -- and 1 GHz if/when the 20x version is available. Of course, with that big a multiplier, a big fast cache is very very important so the CPU doesn't spend all its time waiting for memory access. It's conceivable that IBM could use a 12x, 16x, 20x, etc. multiplier on the G3, but with the G3 near the end of its life as far as Apple is concerned, the potential market probably doesn't justify the expense of redesigning the chip. The future belongs to the G4, which has the "velocity engine" and supports multiple processor designs. -- Dan Knight, president /"\ ASCII Ribbon Campaign Cobweb Publishing, Inc. \ / No HTML/RTF in email http://cobwebpublishing.com X No Word docs in email / \ Respect Open Standards! <http://maccentral.macworld.com/news/9910/27.deb.shtml> -- G-List is sponsored by <http://lowendmac.com/> and... Small Dog Electronics http://www.smalldog.com | Refurbished Drives | -- We have Apple Refurbished Monitors in stock! | & CDRWs on Sale! | Support Low End Mac <http://lowendmac.com/lists/support.html> G-List list info: <http://lowendmac.com/lists/g-list.shtml> --> AOL users, remove "mailto:"; Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive: <http://www.mail-archive.com/g-list%40mail.maclaunch.com/> Using a Mac? Free email & more at Applelinks! http://www.applelinks.com
